Melanoma In Situ: What Stage 0 Means and How to Treat it

Melanoma in situ is also called stage 0 melanoma. It’s the stage of cancer when cancer cells have developed only in the top layer of your skin (epidermis). This article explains melanoma in situ, including what it looks like and what causes it. It also covers the stages, treatment, and prevention of melanoma.

Melanoma in situ is also known as stage 0 melanoma. It’s the initial stage of melanoma when the cancer cells are contained in the top layer of skin, where they first started to develop. They have not spread to deeper layers of your skin.

Although the cells are cancerous, some healthcare professionals refer to melanoma in situ as “pre-cancer.” This is because the cells cannot spread to other parts of your body.  In other words, they are not invasive.

Melanoma is the third most common type of skin cancer. It’s considered the most dangerous because it tends to spread to other parts of the body, including vital organs.

When a melanoma spot reaches the size of a dime on your skin, it has a 50% chance of spreading.

Any change in the way an area of skin looks or feels may be a sign of melanoma. This includes:

• a new spot on the skin
• a skin spot that is growing or changing in shape or color
• a spot that appears different than other skin spots you have

Melanoma in situ can appear as an unusual:

• blemish
• lump
• marking
• mole
• sore

Other melanoma warning signs include:

• a sore that doesn’t heal
• pigment that is spreading outside the border of a spot
• new swelling or redness outside the border of the mole
• pain or tenderness
• itchiness, scaling, bleeding, or oozing
• a bump or lump

To determine how serious your cancer is, your doctor will try to find out if it has spread and, if so, how far. This is called “staging.”

The staging system most often Trusted Source American Cancer Society Highly respected international organization Go to source used for melanoma is the TNM system by the American Joint Committee on Cancer (AJCC). It’s based on three key elements:

• the extent of the main (primary) tumor (T), how thick or deep the tumor has grown, and if there is a breakdown of skin (ulceration)
• the spread to nearby lymph nodes (N)
• the spread (metastasis) (M) to distant lymph nodes or organs

The earliest stage of melanoma is stage 0 (melanoma in situ). After that, melanomas range from stage I (1) to stage IV (4). Stage I cancers are less advanced, have spread less, and often have a better prognosis than higher cancer stages.

Some researchers believe changes in several genes can cause cells to grow out of control. These gene mutations, which can be inherited or acquired, may develop into melanoma.

There are also many risk factors for melanoma, though experts aren’t clear about how they may cause cancer. Risk factors for melanoma include:

• ultraviolet (UV) light exposure
• moles or freckles
• light skin that burns easily
• blonde or red hair, and green or blue eyes
• melanoma in other family members
• history of skin cancer
• weakened immune system
• being older
• being male assigned at birth

The ideal treatment for melanoma in situ is surgical excision. This is when a doctor removes the cancer and an area of skin around it.

Sometimes surgery is not recommended for cosmetic reasons or because a person has another condition. In this case, a doctor may recommend imiquimod (topical medication) or cryotherapy (freezing) to destroy the tumor.

Treatment for melanoma depends on the stage of your cancer and how deeply it has grown. You may need a combination of treatments. Melanoma treatments include:

• excision: surgery to remove the cancer and a margin of skin around the cancer
• lymph node dissection: surgery to remove nearby lymph nodes Trusted Source American Cancer Society Highly respected international organization Go to source
• Mohs surgery: a procedure to remove the cancer but leave adjacent healthy tissue
• radiation therapy: after surgery, destroys any remaining cancer cells or stops new cells from forming
• chemotherapy: medication to destroy fast-growing cells
• targeted therapy: medications that target cancer cells and shrink the cancer
• immunotherapy: IV medication to help your own immune system recognize and destroy cancer cells

There are two main ways you can help prevent melanoma.

One of the best ways to prevent melanoma is to protect your skin from UV rays. You can do this by:

• limiting time spent in the sun
• staying in shady areas when outdoors
• avoiding the use of tanning beds
• wearing a hat or other head cover in the sun
• applying sunscreen to exposed areas of your skin

It’s also important to do regular skin checks for five tell-tale signs of melanoma. You can use the ABCDE rule for skin cancer to help you remember them:

• A for Asymmetry: With melanoma, one half of the spot is not like the other half.
• B for Border: A melanoma spot has an irregular or scalloped border (not clearly defined).
• C for Color: Melanoma has varying shades of color from one area to the next. This includes shades of tan, brown, or black, or areas of white, blue, or red.
• D for Diameter: Melanoma spots are typically larger than 6 millimeters. This is about the size of a pencil eraser. But when diagnosed, melanomas may be smaller.
• E for Evolving: It’s important to watch the spot to see if it’s different from others, or if it evolves or changes in size, shape, or color.

Learn more about the ABCDEs of melanoma.

Melanoma in situ is stage 0 melanoma. This is when cancer cells are contained in the top layer of your skin and have not spread to deeper layers.

Researchers aren’t sure what causes melanoma in situ, but some believe changes in several genes and other risk factors can play a role.

Signs and symptoms of melanoma in situ include any change in the way an area of your skin looks and feels. Doctors use a staging system to diagnose how serious the cancer is and how far it may have spread.

The main treatment for melanoma in situ is surgical removal. Other options are topical medication or cryotherapy (freezing). To prevent melanoma, do regular skin checks and protect your skin from UV rays.